I like the one I got a shot of the other day "Non Portable Water" (uh...de tank was heavy I guess..)

Years ago we put up a sign on a tree on the way to Toco that said "Stop and Drink" a couple weeks later someone added a spray paint arrow going down to the bottom of the tree with the by line "and Pee"

But I think my fav was the nursery down in La Brea called "De Chirren Pen"

"Nan is an incredibly talented writer, who has that rare ability to transport you to wherever she is writing about. She captivates you with imagery and local knowledge that only a well heeled traveller could possibly possess. The result is not only authentic but very beautiful writing."